The expression of proteins in bacterial cell free synthesis systems is a well established technique for expressing recombinant target proteins. Extracts can be made from bacteria expressing or overexpressing proteins of interest to provide bacterial cell free synthesis systems having altered properties depending on the protein. However, overexpression of proteins during bacterial growth frequently results in slower growth rates for the bacteria and lower protein synthetic activity in extracts prepared from the bacteria.
Further, expression of recombinant proteins from such extracts often leads to improper folding and loss of biological activity. The use of protein chaperones can improve the proper folding and biological activity of proteins Thus, there remains a need for improved bacterial cell extracts for expressing recombinant proteins that are prepared from bacteria overexpressing chaperones where such extracts can synthesize large amounts of properly folded protein. These and other needs are provided by the present invention, as set forth below.